1. Field of the Invention
The present invention relates, in general, to an air purification device with oxygen-supplying function and, in particular, to an oxygen supplier and an air purification device useful in indoor air conditioners or automobiles.
2. Description of the Prior Art
As well known to those skilled in the art, traditional examples of a process of supplying oxygen into the passenger compartment of an automobile include a pressure swing adsorption (PSA) process using an adsorbent such as zeolite and a process using a gas separation membrane. The PSA process is applied to supply oxygen enriched air with oxygen purity of 80% or higher, and the gas separation membrane process is used to yield oxygen enriched air with relatively low purity oxygen of 30% or higher. The gas separation membrane process usually requires a higher pressure than the PSA process.
However, these conventional processes, in which oxygen is separated from air using compressed air, are disadvantageous in that an adsorbent usually used in the PSA process, for example, a synthetic zeolite, absorbs moisture due to a vapor condensation phenomenon occurring when high temperature and pressure air compressed by an air compressor comes in contact with relatively cool room air, thereby reducing oxygen separation efficiency. In addition, the gas separation membrane process is disadvantageous in that: oxygen separation efficiency is reduced by moisture, like the PSA process; a lubricant in the air compressor is mixed with compressed air in the case of using an oil lubricating type air compressor having greater durability, and durability of the air compressor is poor in the case of a non-lubricating type air compressor; air compression is limited; a temperature of the air compressor is excessively high; and power consumption is large in the case of a motor type compressor using an automobile electric power source.
In other words, air is compressed to two to four atm of pressure and then supplied into an adsorption bed, and nitrogen adsorbed by the adsorbent in the adsorption bed is desorbed under atmospheric pressure in the case of the pressure swing adsorption process. This conventional process using the air compressor has disadvantages of serious noise pollution, poor durability and excessive power consumption when used in an automobile.
A traditional oxygen supplier for automobiles is a device in which atmospheric air is sucked to separate a small quantity of oxygen from air and oxygen is supplied into the automobile, and a separate air purification device is needed so as to purify air in the automobile.
A vacuum swing adsorption (VSA) process of generating oxygen enriched air with the use of an adsorbent by generating a pressure difference using a vacuum pump, not using the air compressor, has been used to generate oxygen enriched air in great quantities for a long period, in which atmospheric air passes through an adsorption bed under atmospheric pressure, and nitrogen adsorbed in the adsorption bed is desorbed by creating a vacuum in the adsorption bed. The VSA process is advantageous in that noise pollution is reduced, and disadvantages of the PSA process occurring in the case of using an oil lubricated device are avoided. However, this VSA process can only be applied to not a small-scale oxygen generation process but a large-scale commercial oxygen generation process. In the case of being used in the small-scale oxygen generation process, the VSA process is used in combination with PSA process, that is to say, in the form of a VPSA combination process to increase productivity and purity of oxygen enriched air. An example of such VPSA combination processes using a central vacuum line in a building is disclosed in Korean Utility Model Registration No. 20-0219405, and U.S. Pat. No. 5,370,728 also describes a VPSA process. Additionally, U.S. Pat. Nos. 5,266,102 and 5,656,067 each suggest a modified VSA process.
The reason why the VSA process is combined with the PSA process is that oxygen separation efficiency is improved and high purity oxygen is obtained. Meanwhile, it is reported that humans feel refreshed when an oxygen concentration in air is higher than in atmospheric air by ones of %, but oxygen with 90% or higher purity is rather harmful than good to humans. A conventional PSA oxygen separator generates highly pure oxygen of 80% or higher purity, and so direct use of the conventional PSA oxygen separator may cause problems such as fire or oxygen toxicity. Accordingly, it is preferable that a gas separation membrane process generating relatively low purity oxygen, or a modified PSA process generating low purity oxygen in a maximum quantity, instead of the conventional PSA process generating high purity oxygen such as medical oxygen, is applied to separate oxygen from air. Furthermore, when the VSA process having been applied to large-scale applicants is applied to small-scale oxygen separation processes, the VSA process may be preferably applied to automobiles in consideration of low purity oxygen generation.
Therefore, the present invention has been made keeping in mind the above disadvantages occurring in the prior art, and provides an air purification device with oxygen-supplying function according to the VSA process, a kind of the PSA process, in which oxygen enriched air is produced from air using a vacuum source in the automobile, or using a vacuum pump or an oil lubricated type vacuumizing device driven by an engine of the automobile, air in the automobile is sucked by a vacuum pump, the sucked air is purified by a dust collector or a filter such as activated carbon, oxygen enriched air is produced from air by an adsorbent such as zeolite, and the oxygen enriched air is supplied into the passenger compartment of the automobile. As described above, if only the VSA process is used to produce oxygen enriched air from air, oxygen separation efficiency is poor, and thus the VPSA process in which the VSA process is combined with the PSA process is frequently used. However, the air purification device according to the present invention is based on the VSA process using only vacuum because of various disadvantages of applying an air compressor to the automobile. Because the vacuum swing adsorption process is used to operate the air purification device, highly pure oxygen is not generated, thus preferably supplying air with an oxygen concentration not harmful to human health into the automobile.
According to the present invention, drivers and passengers of a car are refreshed because a desirable oxygen concentration of air is maintained in the automobile by sucking air in the automobile, purifying air, and supplying purified air with a desirable concentration of oxygen into the automobile.
Furthermore, the present invention provides a method of separating oxygen from air passing through an adsorbent, comprising the steps of releasing nitrogen adsorbed in the adsorbent such as zeolite using a vacuum pump and sucking air in the automobile into an adsorption bed vessel under vacuum.
Therefore, it is an object of the present invention to supply oxygen in conjunction with purified air into a room or into an automobile.
It is another object of the present invention to provide an air purification device for an automobile with oxygen-supplying function, which sucks air in the automobile to generate air with a desirable concentration of oxygen, and allows the resulting air to pass through a dust collector, zeolite, activated carbon, an antimicrobial filter, an anion generator, and a scent generator etc., thus allowing users in the automobile to feel refreshed.
It is another object of the present invention to prevent an adsorbent such as zeolite from adsorbing moisture due to a vapor condensation occurring when hot compressed air passing through an air compressor comes in contact with cool atmospheric air.
It is another object of the present invention to prevent a lubricant from containing compressed air when an oil lubricated type air compressor is used to overcome poor durability of the air compressor, by using a difference between low pressure due to a vacuum pump and atmospheric pressure.
It is another object of the present invention to provide an oil circulating vacuum pump of an oxygen supplier, driven by an automobile engine, having advantages of low noise, long life span, and high flux.
It is another object of the present invention to avoid disadvantages of a conventional pressure swing adsorption process such as vibration and noise without a high pressure safety device, a pressure controller, and a moisture separator.
It is another object of the present invention to avoid disadvantages of a pressure swing adsorption process by applying a vacuum swing adsorption process into an automobile.
It is another object of the present invention to provide a device for supplying air into an adsorption bed using a single vacuum source and releasing oxygen enriched air from the adsorption bed.